Inktober is a yearly art challenge that happens in October. More can be found at the official website: https://inktober.com

Idea is as simple as that: there is a list of 31 prompts, and you have to create a piece every day of October on the given topics. in a traditional challenge you are to use ink, but this days any form is good: challenge is here to boost your creativity. 

See below all 31 of my interpretations.